Esters of methacrylic acid



Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE 2,129,662 ns'reas orMETHACRYLIC ACID of Delaware No Drawin 6 Claims.

The present invention relates to new materials,

to methods ticularly to the esters of for their preparation, and moreparmethacrylic acid with aliphatic monohydric saturated straight andbranch chain primary alcohols. An object of the present invention is toprovide a new composition of matter and a process for its preparation. A

further object of the invention is to provide a new polymerizablecomposition gether with a process still further object of of mattertofor its polymerization. A the invention is to provide a process forthe preparation of the methacrylic taining more'than five cule, whichmay be obtained by the ester interchange method of interacting a lowerester of methacrylic acid with the alcohol in the presence of a suitablecatalyst. Another object is to provide methacrylic acid esters, such, to

r example,

as the methaorylate of stearyl, lauryl, cetyl,

myrlstyl alcohols and the like. of the invention Another object is toprovide mixtures or interpolymers or the polymerized resin with otherpolymerizable acrylic acids.

the invention will hereinafter appear.

There have been prepared in accord with this invention valuable whichhave been found acrylic acid esters of saturated straight and compoundsof methacrylic and Other objects and advantages of esters of methacrylicacid useful as prepared and These cohols containing more than fivecarbon atoms in the molecule such, for example, as methacrylic acidesters of the primary straight and branch chain hexyl, heptyl, octyl,

nonyl, decyl,

dodecyl,

and higher equivalent and homologous substituted or unsubstitutedalcohols, such as halogen e class, for example, betadiethyl aminoethanol; stearyl alcohol, lauryl alcohol, cetyl alcohol, myristylalcohol, the mixture of primary alcohols obtained by the catalytichydrogenation of carbon oxides under elevated temperatures and pressureshaving more or amino substituted alcohols of th than five carbon atoms,

obtained in accord with the process described in the Roger Williams U.S. Patent No. 1,844,847, or any process producing similar products,

the mixture of primary alcohols,-

containing more than five carbon atoms, obtained from the catalytichydrogenation of cocoanut and like oils, in accord with the Lazierprocess described in his copending application Ser. No.

5, 1931, which discloses a process for the preparation of alcohols bythe catalytic hydrogenation vated temperature and of glycerides underelepressure, or by any suitable process for the hydrogenation of thoseoils,

and other equivalent alcohols.

to illustrate methods of & Company, wilmi l I. du Pont de Nemours Del.,a corporation g. Application July 14, 1934, Serial No. 735,274

The following specific examples are furnished preparing the newcompositions of matter, but it will be understood that the invention isnot limited to the details therein given.

Example 1.186 parts of lauryl alcohol were mixed with 400 parts ofmethyl methacrylate, 2.9 parts of concentrated sulfuric acid and 24parts of hydroquinone (all parts are given by weight) and the resultingmixture heated on the water bath until the solution was complete. Thesolution was then heated on an oil bath, held at a temperature ofapproximately 150 C. under a 48" fractionating column fitted with acondenser arranged for controlling reflux. Distillate was collected atsuch a rate that the temperature at the head of the column remained atthe boiling point of the methanol-methyl methacrylate binary (64). Thecold reaction mixture was neutralized and then washed and dried over asuitable desiccating medium. The solvents were removed from the driedproduct by fractional distillation, and the ester finally separated byfreetionation under reduced pressure. A 41.3% yield of laurylmethacrylate was obtained. It had a boiling point of 142 C., at 4 mm.,and a saponification number of 215,theoretical 221.

Example repeated with 800 parts of methyl methacrylate, 372 parts of amixture of alcohols obtained by the hydrogenation of cocoanut oil, 6parts of concentrated sulfuric acid, and 45 parts of hydroquinone. Thetemperature of the oil bath was maintained at approximately 150-160 C.,and after 4 hours a 51% yield of the methacrylic acid ester wasobtained. This ester had a density at 20 C. of 0.874 and asaponification number of 214.

Example 3.-153 parts of a mixture of oxygenated organic compoundsboiling between 133147 0., obtained by the catalytic hydrogena- 2.-Theprocess of Example 1 was acrylate, 350 parts of benzene, 35 parts ofhydroquinone, and 12 parts of p-toluene sulfonic acid, 41-120, are mixedand warmed on a water bath until solution was complete. The solution wasthen heated on an oil bath maintained at a temperature of 130-140 C.under a 48" fractionating column fitted with a condenser arranged forcontrolled refiux. The distillate, which consisted of a benzene-methanolbinary, was collected at such a rate that the temperature at the head ofthe column remained at 58-59". Heating was continued until thetemperature at the head of the column could not be maintained at 58-59"C. The progress of the reaction was followed by measuring the amount ofmethanol in the distillate as shown by the portion that would dissolvein water. The cold reaction mixture was neutralized and then washed anddried over a suitrepeated with able desiccating, medium. The solventswere removed from the dried product by fractional distillation, and theester finally separated by fractionation under reduced pressure. A 25%yield of a mixture of methacrylic esters of the oxygenated compounds wasobtained. The esters had a boiling range of 67-70 C. at 9 mm., a densityof 0.880 at 20 C., and a saponification number of 295.8.

Example 4.-The process of Example 3 was 400 parts of methylmethacrylate, 270 parts of stearyl alcohol, 300 parts of benzene, 3.5parts of sulfuric acid (concentrated) and 30 parts of hydroquinone. Thetemperature of the oil bath was maintained at approximately 140-150 C.,and after 7 hours a 75% yield of stearyl methacrylate was obtained. Theester had a melting point of 28-29" C., and a saponiflcation number of157,-theoretical 166.

Example 5.100 parts of betadiethyl amino ethanol, 340 parts of methylmethacrylate, 450 parts of dry benzene, and 20 parts of p-phenylenediamine were mixed and heated to boiling on an oil bath under a 48"column. After the solution had started to boil the addition of thecatalyst, a methanol solution containing 20% sodium methylate, wasstarted and it was added in small portions at short intervals while thereaction was being carried out on a temperature of approximately130-145" The total catalyst added was approximately 20 parts. Thecatalyst solution was added from a dropping funnel thru a side neck inthe reaction flask. The course of the reaction was followed by measuringthe amount of methanol (water soluble portion) in the distillate.Theaddition of catalyst was generally stopped a short time before thetheoretical amount of methanol was obtained. The product wasneutralized, dried, vacuum distilled and freed from betadiethyl aminoethanol by repeated extraction with water. A 52% yield of betadiethylamino ethyl methacrylate was obtained.

an oil bath maintained at;{: C.

Other methods may, of course, be employed for the preparation of theenumerated methacrylates such, for example, as are disclosed in thecopending applications of Barrett and Strain Ser. Nos. 735,275, 735,276and 735,278, filed on even date with this application and disclosingprocesses for preparing methacrylates by treating alcohols withmonomeric acid halides and monomeric methacrylic acid esters of thelower alcohols, or by any of the well known suitable esterification orester interchange processes.

The methacrylates, as prepared in accord with the examples, are usuallymobile liquids, but may sometimes be solids. The esters as thus proeduced are monomeric and may be polymerized, according to the invention,by means of heat, light, and/or a catalyst, e. g., as described for thepolymerization of organic vinyl esters in British specification15,271/1914. Preferably a catalyst such as O ygen, ozone, an organicperoxide, an ozonide, etc., is employed. Other catalysts which may beused include aluminum sulfate, boron fluoride, the mineral acids, e. g.,hydrochloric and sulfuric acids, as well as the organic acids and more.particularly acetic and methacrylic acids, etc., as well as theanhydrides and acid halides of such organic acids; metal salts of fattyacids and resinic acids, e. g., cobalt linoleate and resinate, manganeseoleate and rosin, etc. The polymerization may be effected in thepresence or absence of a solvent for both monomer and polymer, or in thepresence of a solvent for the monomer and a non-solvent for the polymer,or the monomer may be emulsified and then polymerized. Preferablypolymerization is carried out at a moderate temperature, 1. e., between60-100 C. or higher, may be employed. The polymerization reaction isusually strongly exothermic and it may be necessary to control thetemperature by cooling devices. tho polymerization may be carried out inapparatus which may or may not be provided with condensing devices, orin suitable pressure equipment.

As indicated, various methods may be employed for polymerizing themonomeric esters of methacrylic acid and it has been found that theproperties of the resins, the physical properties to a large extent andthe chemical properties to a lesser extent, are altered considerably bythe type ofpolymerizing process utilized. The process described in thecopending applications of D. E. Strain, Ser. Nos. 668,080 filed April26, 1933, and 704,753 filed Dec. 30, 1933, may be used, if desired.

Methods illustrating the polymerization of the esters will now bedescribed, but it will be understood that other suitable polymerizingprocesses may be employed.

Example 62-4315 weight) of lauryl dissolved in 189.2

, provided with a stopper, then 0.5 part of powdered benzoyl peroxideadded to this solution. After the benzoyl peroxide was all dissolved, 13parts of water insufficient to cause permanent turbidity was added. Thebottle was securely closed and set in an oven at approximately 65 C.After the polymerization was complete in approximately 48 hours, themixture was allowed to cool. The liquid was decanted. The resin wasremoved from the bottle, was cut into small pieces and was dried in avacuum desiccator. The polymer was obtained in a 90% yield as acolorless, sticky, very viscous liquid resin which was relativelyinsoluble in all common solvents.

Example 7. The polymerization process of Example 6 was repeated using100 parts of the monomer obtained from the raw material and by theprocess of Example 2, 310 parts of methanol, 1 part of benzoyl peroxide,and 4 parts of water. After 5 days at 65 C., an yield of a fused,transparent, amber colored, rubber like, very sticky, polymer wasobtained which was relatively insoluble in all common organic solvents.

Example 8.-The polymerization process of Example 6 was repeated using 20parts of monomer obtained from the raw material and by the process ofExample 3, 150 parts of methanol, 0.2 part of benzoyl peroxide, and 30parts of water. After 1 day at 65 C., a yield of the polymer wasobtained as fused, glassy, particles which were soluble in toluene andrelatively insoluble in butyl acetate, gasoline and acetone.- A 5%solution in toluene gave a viscosity of 0.024 poise at 25 C. The polymeris compatible with nitrocellulose.

The resin was placed in a disk shaped mold in which it was subjected toa temperature of C., and a pressure of approximately 5,000 pounds persquare inch for approximately 15 minutes. A water-clear molded disk wasobtained which softened at a temperature of 32 C.

The compatibility with nitrocellulose was determined by dissolving anequal volume of a 5% polymerized ester in a acetate. The resulting partsof nitrocellulose to dry at room temperature.

'' crylic esters or other derivatives.

which is Example 9.-Undiluted stearyl methacrylate monomer containing 1%benzoyl peroxide was heated to a temperature of 65 C. After 48 hours thepolymer was obtained as a hard, brittle wax which upon heating becomestransparent and slightly rubber-like at about 38 C. The polymer wasrelatively insoluble in all common organic solvents.

Example 10.-Undiluted diethyl aminoethyl methaorylate monomer containingno polymerizing catalyst polymerizes at lowtemperatures very 'readily,in fact polymerization has occurred at temperatures as low as 0 C.Polymerization for 18 hours at 100 0., produced a 100% yield of abubble-free, amber colored, transparent, firm but rubbery, slightlytacky polymer which gelled in toluene but was relatively insoluble inbutyl acetate, gasoline and acetone.

.Valuable products may be obtained by utilizing the polymers of theesters described. herein together with equivalents or homologues thereofadmixed with other polymeric, acrylic, or metha- Especially valuableproducts result if the monomeric esters are mixed prior to theirpolymerization; by this method interpolymers having a wide range ofcharacteristics are made. Due to the unique characteristics of methylmethacrylate polymer a hard resin having a high melting point, itsadmixture with the polymeric esters of methacrylic acids hereindescribed or interpolymers thereof are particularly well adapted formany uses.

The esters of methacrylic acid are particularly well suited forthermoplastic molding. The ester may be'polymerized and/orpreformedprior to placing in the mold and then may be molded in accord with theusual procedural steps employed particularly in the molding of methylmethacrylate as described in the Rowland Hill copending application,Serial No. 641,113. The mold preferably is hot, prior to theintroduction of the polymerization product, is then closed and thematerial so confined, heated and pressed, the temperatures ranging fromapproximately Bil-450 C., and pressures from 200 pounds per square inch,upward, are usually sufficient to give a suitably molded product. Thepresence or absence of plasticizers will, of course, alter considerablythe molding conditions and it is usually advantageous to have presentplasticizers to alter the physical characteristics of the resultingproduct to fit the particular need for which the molded article is to beused.

The masses resulting from polymerization can immediately (1. e., in thestate they have been obtained) be made into useful articles. It ispossible to obtain the required articles if, for instance, thepolymerization be carried out while the initial material is in asuitable mold, for instance one of steel or glass, so that.v thearticles, for example umbrella handles, fountain pen barrels, buttonsand the like, are obtained directly from the mold. Or if desired themasses may be worked to the required shape by softening with suitablesofteners or plasticizers in the presence of volatile solvents and,after shaping, evaporating the solvent.

The polymerization products may be worked into the required shapes invarious ways, for example, they can be softened and kneaded, rolled,compressed, drawn into wires, threads or the like, or the masses can bemixed with additional substance, and rolled into plates, or films, orthey may be pressed into the required shapes such as buttons, combs andthe like.

The solid masses can be worked by cutting, sawing, filing, or the like,whether they be obtained directly by polymerization, or after specialtreatment of the polymerized masses. These shaped articles may bepolished, and parts connected together by smearing the faces to beconnected with a suitable solvent, such as acetone, epichlorhydrin, orthe corresponding methacrylic acid ester.

The polymerization product dissolved in a suitable solvent which may ormay not be the monomer may be transformed into a useful article, e. g.,films by casting and then evaporating the solvent, or by extrudingthrough a suitable orifice into a precipitating bath or dryingatmosphere. The polymer may be recovered from such solutions byprecipitation with a suitable nonsolvent for the polymer.

The properties of the resulting masses may be widely varied bymodification with plasticizers,

e. g., dibutyl phthalate, tricresyl phosphate, etc., drying, semi-dryingand non-drying oils, synthetic and natural resins, waxes, bitumens,cellulose derivatives, e. g., cellulose nitrate and ethyl cellulose,etc.. pigments, fillers, and dyes, etc. Thus it is possible to produceinstead of hard glass-like masses, also soft and flexible masses.Likewise, by the addition of suitable coloring means, it is possible toproduce masses, or objects, having any desired color effects. Theincorporation of the additions can be effected either before, or during,the polymerizing process, or the additions can be made to the alreadyformed polymerization products in a suitable condition.

If the polymerization of an organic methacrylic acid ester, be carriedout in an incomplete manner, a syrupy solution of the polymerizationproduct containing some unchanged methacrylic acid ester, is obtained.This product can be utilized either directly, or along with othersolvents, or diluents, for the production of substances to be used forcoating, painting, or impregnating purposes If, for instance, a poroussubstance such as wood, paper, textile fabric, artificial stone, or thelike be coated with the said syrupy solution or be impregnatedtherewith, very resistant coating and impregnations are obtained oncompleting the polymerization'of the coatingypainting, or impregnation,for instance by exposing the article to artificial or natural light, orby heating it, or by employing both light and heat. In this case aportion of the unchanged methacrylic acid ester in the syrupy solutionmay or may not be evaporated while another portion may be converted intothe solid polymerization product. The articles thus treated haveimparted to them a very high resistance to external influences, e. g.,resistance to water, acids, alkalis, and atmospheric changes.

The said syrupy mass can be mixed with comminuted matter, such, forinstance, as ground (cork, or ground wood, fibrous substances, mineralfillers, or the like, and the mixture be made into the proper shape andthe unchanged methacrylic acid esters in the articles be converted bysuitable polymerization into the solid final product.

It is also possible to start from solid, semi-solid, or' plasticpolymerization products of the methacrylic acid esters, these beingsoftened by heating them by themselves, or with suitable solvents, andusing them in their softened state. On

by varying cooling, or on the evaporation of the diluent, that may stillbe present, the product is converted into the solid lacquer-form.

It is obvious that mixtures of various polymerized methacrylic acidesters can be used for laequering, painting, or impregnating inaccordance with this invention. It is likewise obvious that the whollyor partly polymerized esters can be mixed with suitable additionalsubstances to modify the properties of the lacquering, painting, orimpregnating materials in any desired manner. As additions of this kindthere may be mentioned oils (such, for instance, as castor oil), dyes,powdered substances (such as zinc oxide), camphor, camphor substitutes,and the like.

In accordance with this invention it is possible to obtain valuableproducts if the said polymers be dissolved, or softened, in suitablesolvents and then be converted again to the solid state. The productsthus obtained may be used for purposes for which cellulose esters havehitherto been used, namely, as substitutes for horn, amber, artificialresins, lacquers, for impregnation purposes, and also for the productionof films, interlayer for sives, artificial threads, and the like.

The products thus formed have the advantage over products made fromnitrocellulose in being slower burning and odorless. By the addition ofsuitable agents, the strength and hardness of the products-may bemodified within wide limits so that it is possible to manufacture bothhard, horn-like substances and soft and more pliable products. Theproducts may also be modified the conditions of the polymerization.

The monomer may be polymerized in the presence of a solvent and thesolution used as such or the polymer recovered from the solution byevaporation or precipitation methods. In many cases, however, it is moreprofitable to use an amount of solvent insufiicient to produce a freelyflowing solution, so that soft plastic masses are obtained which can bepressed, kneaded, rolled or drawn into shape, or formed into blocks,plates, or films.

Plasticizers or other modifying agents may be added to the monomer priorto polymerization or directly to the polymerized product, it beinggenerally desirable to employ a plasticizer which is soluble in thepolymer and'the monomer, altho it is not essential that the dualsolubility characteristics be present. Thus plasticizers or softeningagents, such as, for example camphor; phthalates, such as ethyl, propyl,isopropyl, butyl, isobutyl, cyclohexyl, methyl cyclohexyl, or benzylphthalate or phthalates of the mixed type, such as cyclohexyl butyl,benzyl butyl or butyl lauryl phthalate; esters of other dibasic acids,such as the ethyl, propyl, isopropyl, butyl, isobutyl, cyclohexyl,methyl cyclohexyl or benzyl esters of succinic, fumaric, tartaric,adipic and sebacic acids; esters of monobasic acids, such as the butyl,isobutyl, cyclohexyl, methyl cyclohexyl, benzyl or lauryl esters oflauric, laevulinic, benzoic, benzoyl propionic and benzoyl benzoicacids; esters of polyhydric alcohols, e. g., glycol and glycerol, suchas glycol benzoate, glycol laevulinate, triacetin, tripropionin andtributyrin; the ether alcohol esters of the polycarboxylic acids, e. g.,methoxy ethyl and ethoxy ethyl phthalate; substituted toluenesulphonamides, such as ethyl paratoluene sulphonamide; substitutedamides,

safety glass, pressure adhesuch as tetraethyl phthalamide, tetrabutylzuccinamide, tetrabutyl I adipamide, tetra-ethyl phthalamide;hydrocarbons, such as, dixylyl ethane; halogenated hydrocarbons, such aschlorinated diphenyls and dichlordibenzyl; compounds such as dicresoxyethyl ether; and drying, non-drying or semi-drying oils, such as castoroil, cotton seed oil, linseed oil, and the like. These additions alsofacilitate later mechanical treatment, as cutting, sawing, andPolishing.

. The polymerized esters, merized esters with dissimilar polymerizableesters or other polymerizable compounds of methacrylic or acrylic acids,or vinyl compounds, or interpolymers of the esters with such othercompounds, may be used advantageously as safety glass interlayers. Thesepolymerized esters, mixtures thereof, or interpolymers thereof may beplasticized or otherwise modified as desired. The compositions may becompounded with glass in an unbolymerized, partially polymerized, orcompletely polymerized condition. When compounding the safety glass withthe unpolymerized or partially polymerized compositions, thepolymerization may be eii'ected by sub- Jecting the sandwich of glassand compound to suitable application of light and/or heat.

From a consideration of the above specification it will be realized thatvarious changes may be made in the process or product without departingfrom the invention or sacrificing any of its advantages.

We claim:

mixtures of the poly- 1. A mixture of methacrylic acid esters of themixture of primary, straight and branch chain alcohols obtained by thecatalytic hydrogenation of carbon oxides under elevated temperatures andpressures.

2. A new composition of matter comprising a mixture of methacrylic acidesters of the mixture of primary straight and branch chain alcoholsobtained by the catalytic hydrogenation of carbon oxides under elevatedtemperatures and pressures and having a boiling range of 6770 C., at 9mm.

3. A polymeric mixture of methacrylic acid esters of the mixture of.primary, straight and branch chain alcohols obtained by the catalytichydrogenation of carbon oxides under elevated temperatures andpressures.

4. An interpolymer of a methacrylic acid ester of an aliphaticmonohydric saturated primary alcohol containing more than five carbonatoms in the molecule and another polymerizable compound selected fromthe group consisting of a derivative of acrylic acid and a derivative ofmethacrylic acid.

5. A process for the preparation of a methacrylic acid ester of analiphatic monohydric saturated primary alcohol containing more thancarbon atoms in the molecule, which comprises reacting methylmethacrylate with an aliphatic monohydric saturated primary alcoholcontaining more than 5 carbon atoms in the molecule.

6. An interpolymer of a methacrylic acid ester of an aliphaticmonohydric saturated primary alcohol containing more than five carbonatoms in the molecule and another polymerizable ester of methacrylicacid.

HAROLD J. BARRETT. DANIEL E. STRAIN.

ether

